Improvement in springs



HOPSON 8a MASON.

Spring.

Patented sepnf?, 1869.

Wznesses.

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NECTICUT.

' Laim Patent N0. 94,603, dared september 7, 1869.

IMPROVEMENT IN SPRINGS.

The Schedule referred to in these Letters Patent and making part of the same.

To all whom t't may concern:

Be it known that we,.GEonGE HOPSON and J o- SEPH H. MASON, ot' Bridgeport, in the county of Fairfield, and State of Connecticut, have invented certain new and useful Improvements in the Construction of Springs ;v and we do hereby declare that the following is a fulland exact description thereof.

Our invention relates to what are commonly known as elliptic springs, haltelliptic, cross-springs, C-sprin gs, and, generally, Vto all forms of metal springs in which the steel or other elastic material is constructed in separate plates or leaves, mounted face to face, so that one shall support and contribute to the force of the next.

In all springs of this characterit is necessary to provide some means of maintaining the plates or leaves in their, propel' positions relatively to each other; that is, to prevent their*slipping.laterally upon each other, or, in other words, to maintain their parallelism. It has long been common to contribute to this result by making, near the ends, a slot or long depression, extending into or through one of the leaves, with a nipple or beati raised on theface of the next, and fitting inside of theslot or groove. As the spring is bent, the plates or leaves of the spring work or slide upon each othera little, which compels the' bead to travel forward and back in the slot or groove. Itis necessary to make the groove longer than the slot or bead, in order to allow for this motion.' We adopt this mode for guiding and keeping the platesin position,an l also adopt the previously-known mode of producing such groove and such bead; that is to say, we produce the required long depression' by pressure, with a suitable tool, upon one face of a leaf while itis hot, and sufiiciently soft to allow of such indentation; and we produce the bead by forcing out the metal while it is held in a hollow die which has a depression adapted to properly mould the bead.

So vfar as we have yet explained, our construction has been long known and approved.` Itwill be understood, that in raising the head, a punch, or tool of somewhat analogous function, is pressed against the opposite face of theleaf, and' thus a depressionV is caused on that side, partially or exactly corresponding to the bead which is raised on the other side. When thc plates or leavesare bolted together inltheir proper relations to form aspring, thebeads are on one side, and the grooves, as also all the indeiitations opposite the beads, are on the opposite sides or faces of the leaves. i 'g la such spring, every leaf or plate is subject, on one face, to4 a tensile or rending strain-.a force tending to divide itasunder on that surface; and the other face is exposed to a compressive strain--a force tending to contract or crush it together.

In all previous springs of this kind, the bead has been on the compressed side, and the depressions have been o n the distended side -of each plate. Our im provement consists in reversing this arrangement. \Ve produce the bead on the distended side, andv we produce the opposite depression, which forces up the metal for the bead, and also the longer depression, or blind slot, on the opposite face-that is to say, on the face of the plate or leaf which is compressed; in other words, we put the bead on that side of each leaf which is exposed to a tensile strain, and we put the recess on that side which is exposed to -a conipres'siveiforce. This arrangement avoids the dangerous weakening of the spring due to the old construction. l

XVe employ machinery for producing the beads and the sunk recesses in which they traverse, whereby the plates or leaves are treated without distortion in other words, we produce the grooves, which are generally denominated lilind slots, by forcing into the hot steel ofthe leaf a rounded punch of the .proper form-that is to say, an eighth of an inch in width, about the same in depth, and one inch, or thereabouts, in lengthwithout raising any appreciable swell, or in any way deforming or defacing the opposite face of the leaf; and we produce the bead, which is an elevation of corresponding width and height, but of less length-say three-eighths of an` inch in lengthby forcing into one face of the leaf a corresponding punch, and raising a sharply-detined bead of the .proper dimensions, without appreciably disturbing the contourof the other parts of the'leaf.

By our improved arrangement of the depressions and elevations, we not only increase the strength', or

rather, avoid the weakening` of the spring, as compared with the old arrangement, but also obtain a fair surface on all portions of the spring which are in sight.

The old arrangement produced a depression on the inside surface of the inner leaf or plate ofeach spring, and, these being Very much exposed to the eye, espepecially on the lower half of the spring, it has been customary to ll such depression with putty. This barbarous-procedure, when the putty wascovered with paint, produced an imitation of -a fair surface. -Ours makes a really fair surface. The putty was always 1iable to be jarred ont, and, in any event, contributed nothing to the strength or usefulness of the structure. Our spring is, in every part, effective.

Instead of forcing the punch quite through the leaf, as has been heretofore practised in forcing' up the bead, and thus making -tlie bead only a hollpw shell, wetake care to hold the hot material very eectually by the tended side of the spring, but rather increases the mau terial on that side by the presence of the bead there, and the bead, being solid, and strongly connected, is,

in eiect, a strengthening-rib, and contributes to the strength and stiness of the spring, for the short length towhich the: bead extends, Without weakening it at any other point. Y

The sinking of our blind slot cannotcontribute to' .increase the strength of the spring, becauseV there is no corresponding elevation on the opposite face; but we have modied the form of' the blind'slot, in addition to placing it on the compressed side of the spring, and have thus attained, as we believe, the minimum degreeofweakening from this source. Our modiiied form is rounded in every direction-that is to say, there are no re-entering angles in or about it. The groove is not-as deep at each end as atand near themiddle. By this. form, We avoid the weakening which is due to the sharp ,angle heretofore left at each end ofthe slot.

Theadvantages of our invention over that construction still in-common use, in which each slot is ont quite through its leaf or plate, are too obvious to reduire special remark. on both faces, andthe weakening to the spring is obvious, even it the metal is thus punched hot. When, as is usually the case-in that method of manuicture, the punching is eected cold, it not only weakens by the removal of the material in thespace occupied by 'the slot, but it weakens'l by vstraining and partially f cracking the adjacent fm'aterial. We have, in this v specification, confined' attention mainly to the com-parison of this with the previously-known springivhich most nearly resembles it, to wit,that in which there is a blind-slot extending only about half way through the plate, and which We have adopted, with the modiic'ations and improvements herein described.

The accompanyingdi'avvings formY a part of this speciticatiou.

Figure l vrepresents a longitudinal section of a little more than halt' of a light elliptic spring. lhis spring contains only threezplatesA or leaves, andl there is, con-v sequently, asmaller number of depressions and -eleva-. tions than wouldbe required in a spring with more plates, intended for heavy wagons.

Figure 2` is a cross-section Yon th e line S S in fig. 1.

Such slottiug removes the material Figure ltis a longitudinalv section through a portion of a heavy spring, such asis adapted for stout lumbertlle'relative arrangement of the beads and depressions when there are a great number of leaves..

Similar letters of reference indicate corresponding parts in all the figures.. Y

1, 2, 3, 8vo., represent the successive plates, reinforcing or contributing their force to aid each other in the order of their numbers; that is to say, the rst plate, l, receives the load directly; the secondplate, 2, contributes to assist it; the third plate, 3, contrib-v utes again, and so on, for any number of plates.

AA are beads, and a a are the corresponding de pressions, produced by a punch, or analogous tool, in

raising the bead.

It will be understood, as has been above stated, that in the act of producing the bead, the plate is heated and treated by machinery, which holds itl very eliiv'ciently against distortion, While a properly-rounded punch is forced in on one face, and raises the bead on the opposite face. l

C G are the grooves or blind slots. These are produced, by machinery, while the material of the spring is in a heated', and, consequently, soft condition, and is held against distortion, as has been above explained.

The drawingsrepresent the novel parts, with so much of the other parts as seems necessary to explain their relation thereto. The endsof the springs, the cenelevations above referred to, may be constructed and' arranged in any approved manner.

Ve donot .claim a spring in which the compressions are sunk. only partially through the thickness of lthe leaf, and are rounded in contour, as We but 1 We claim as our invention, and desire to secure by Letters Patent- The within-described improvements in leaf-springs, having the beads on the distended side, and the depressions on the compressedside of each leaf, all as and for the purposes herein set forth.

In testimony whereof, we have hereunto' set our names,.in presence of two subscribing witnesses.

' GEO. HOPSON.

JOSEPH H. MASON.

VVituesses: 7 I

C. C. BULLoeK `L. BULLocK.

wagons, railroad-cars, and the like. This figure shows tres, and vall the details other than the depressions and,

have described; 

